This invention relates to compositions and methods for inhibiting corrosion and deposit formation in fuel handling equipment, with reduced or eliminated incidence of fuel filter plugging and internal diesel injector deposits (IDID) in the equipment that eventually employs the final commercially blended form of the fuel. More specifically, the invention relates to inhibiting corrosion from the walls of fuel pipelines and storage equipment and preventing deposits in engines.
Commercial fuels are blends of refinery fuels with certain other additives. In particular, corrosion inhibitors must be added at refineries to ensure the refinery fuel does not corrode the refinery equipment. Thus, while other additives are introduced into the refinery fuel at the refinery or at a fuel terminal to create the commercial fuels, commercial fuel generally includes a mixture of at least the refinery fuel and whatever corrosion inhibitor that was employed at the refinery.
Recently, there has been reported increases in the incidence and severity of, for example, fuel filter plugging and internal diesel injector deposits (IDID) in variously fueled engines using commercial fuels. Among the postulated causes of the plugging and IDID are soaps that form in the refinery fuel from the reaction of acidic corrosion inhibitors with ion containing contaminants in the refinery fuel, such as sodium and calcium containing contaminants. For example, presently dodecenyl succinic acid (DDSA) is added to diesel fuel at the refinery to inhibit corrosion for the period of time the diesel fuel is in storage at the refinery through transport of the fuel in the refinery pipeline to the fuel terminal at which the diesel fuel is blended with other performance additives into a commercial fuel. It is increasingly being discovered that DDSA reacts with sodium contaminants in the refinery fuel, and this contamination leads to soap contamination in the later commercial fuel, ultimately resulting in fuel filter plugging and IDID.
As evidence mounts of this effect, further complications are coming about due to changes in fuel composition, fuel injection hardware, and levels and types of fuel additives in use in the final blended forms of the refinery fuel.
A new and improved additive composition has now been found to inhibit corrosion in refinery fuel, which leads to reduced or eliminated incidence of fuel filter plugging and IDID in engines run on the final blended form of the refinery fuel.